Gleno-humeral Internal Rotation Deficit (GIRD) 

GIRD is an acronym for Glenohumeral Internal Rotation Deficit, a condition that is common in athletes performing repetitive overhead motions such as baseball pitchers, basketball and volleyball players, and swimmers.

Although rare it also in people demonstrating postural impairments who often sit in the same position for a long time. 


What is Glenohumeral Internal Rotation Deficit?

The throwing motion is a complex process that requires extreme force and velocity. Mobility and stability are inversely linked. While performing the throwing motion the humerus is more retroverted than the non-dominant arm and adapts itself.

When these movements happen repetitively the humerus of the shoulder twists at the growth plate leading to permanent adaptations in the bone structure. Retroversion is also detected in the glenoid. In GIRD the shoulder loses internal rotation by 20%. 

During throwing or pitching the extreme force puts a high amount of stress on the static and dynamic stabilizers of the shoulder, including the rotator cuff, joint capsule, and labrum. With each extreme motion without any proper time to heal the patient becomes more vulnerable to injury. 

What causes Glenohumeral Internal Rotation Deficit?

The main cause of GIRD is the instability caused due to intense force applied to the stabilizers in the shoulder which after a point they may not be able to sustain. It happens due to the tightening of the posterior structures of the shoulders which leads to improper shoulder deceleration causing microtrauma. 

Bone adaptability due to repetitive overhead motion leading to compression in the subacromial and coracoacromial regions is also a likely cause. 

Although there have been numerous studies it is still unclear whether GIRD is a cause of shoulder abnormalities or a psychological response to the pathological shoulder.   


Symptoms of GIRD 

Although the typical symptoms are pain and inflammation in the affected area. These are some typical symptoms when the patient is suffering from a GIRD injury:

  • Increase in external rotation of the shoulder and decrease in internal rotation
  • Changes in the structure of the tissue surrounding the bone
  • Hypermobility in the affected arm
  • Laxity in the posterior capsule 
  • Increased retroversion of the long head of the humerus in the glenoid 
  • Lack of muscle strength required to balance maintain dynamic stabilization
  • Alteration in the motion of the scapula 


Diagnosis of Glenohumeral Internal Rotation Deficit?

Diagnosis of GIRD begins with the doctor asking the medical history of the patient. Patients suffering from this injury usually complain about stiffness in the shoulder, prolonged warm-up routine, and loss of velocity. 

As the pain is not specific to a certain portion of the shoulder the doctor will thoroughly check the shoulder and the neck to rule out the possibility of other problems. 

The doctor will carry out a physical examination wherein the loss of internal rotation in the shoulder will be assessed. For this purpose, the doctor will have the patient lie supine then bring both the arms in 90 degrees of the shoulder abduction and 90 degrees of elbow flexion. Maximum passive external and internal rotation will be assessed between the affected and unaffected shoulder. The differences between the rotations will be measured using a goniometer.  

The doctor will also examine posterior shoulder tightness by having the patient lie in a lateral decubitus position with the throwing shoulder facing upwards. With the shoulder in 90 degrees of abduction and the scapula stabilized, the arm is adducted to its maximum extent. Then the posterior shoulder tightness is calculated. It the difference between the throwing and nonthrowing shoulders. Every 1 cm of loss of adduction is equated to 5% of loss of internal rotation. 

If there is a deficit of 4 cm it will equate to a loss of 20% loss of internal rotation leading to a successful diagnosis of GIRD

Almost two-thirds of the patients (mostly pitchers) show a sulcus sign upon an examination which can be attributed due to the laxity of the coracohumeral and superior glenohumeral ligament. 

Physical examination will be followed by radiography.  X-rays will only show the abnormality of the bone structure if any.  MRI scans are more preferable as they will help in showing the thickening of the posterior capsule and damages to the soft tissues.


Treatment for GIRD 

Multiple studies have proven that the patients benefit most from stretching exercises. 

These exercises help in:

  1. Strengthening the posterior capsule 
  2. Improving scapular mechanics 
  3. Increasing the acromiohumeral distance
  4. Restoring both internal and external rotation 

To subside the pain and swelling nonsteroidal anti-inflammatory drugs as prescribed by the doctor can be taken. 

Surgery should only be considered when non-surgical treatments fail to provide satisfactory results.